Ryan Mathews not practicing again

SAN DIEGO -- Running back Ryan Mathews was not on the practice field for the early portion of practice on Friday, the first time he’s missed a Friday practice since suffering an ankle injury against Oakland three weeks ago.

Mathews’ absence is not a good sign for the San Diego Chargers, who need the bruising running back available to provide balance offensively.

Mathews ran for 127 yards, including a 23-yard touchdown, in a 27-20 win against Denver in December. If Mathews can’t go, Danny Woodhead and Ronnie Brown likely will split carries at running back for San Diego.

Mathews appeared to tweak his ankle against Cincinnati last week. He carried the ball only one time in the second half of San Diego’s 27-10 playoff win against the Bengals.

Along with Mathews, guard Jeromey Clary (shoulder) and receiver Eddie Royal (toe) are not practicing on Friday.

The Chargers did receive some good news, with center Nick Hardwick (concussion) clearing the NFL’s concussion protocol and returning to practice on Friday. Hardwick had a helmet and went through individual drills with the first-unit offensive line during the early portion of practice, while Clary watched on the side.

Right tackle D.J. Fluker (ankle) also practiced for a second straight day.